In lamp fixtures intended for outdoor use it is essential that the electrical components be sealed against the entry of moisture into the body of the fixture. In this regard see for example U.S. Pat. Nos. 2,279,595; 2,285,728; and 3,069,537, which disclose light fixtures designed primarily for outdoor installations.
The integrity of the seal is particularly important where the unit is likely to be subjected to severe weather conditions, as might be encountered, for example, on an offshore oil rig. In such installations the lamp fixtures are not only subjected to rain, but also are drenched with ocean spray and often immersed in waves. It will be see, therefore, that a good watertight seal is essential.
Another aspect that must be considered in designing lamp fixtures for such places as offshore oil rigs is the fact, that unlike units which are mounted on land installations, routine lamp maintenance can constitute a hazardous task in that the workmen must often climb over the rig under less than ideal conditions. It is understandable therefore that the replacement of bulbs and any other similar routine maintenance should be capable of being performed as quickly as possible.
The necessity of having a watertight lamp fixture and the desirability of having one in which bulb changes and other routines maintenance can be performed quickly present contrary design considerations. For example, two of the most common ways of providing a water-tight seal is to have a sealing ring that is clamped in place by a plurality of separately operated dogs or other clamps or held in place by a series of bolts. It will be obvious, however, that unlocking each of several clamp mechanisms or manually removing each of the bolts holding a lamp sealing ring in place are time consuming tasks and difficult to perform under adverse conditions.
Thus, a need has existed for a water-tight lamp fixture which will function under severe weather conditions and yet can be opened and closed for bulb changes and the like with a simple, quick acting latching system.